So I currently have a 500w Finnex titanium heater with an Inkbird controller in my 93 gallon cube. I want to get a second heater to put in the sump as a backup. Since I have a cube I need a smaller sized heater for in my sump since I had to get a Trigger system cube sump I dont have alot of room to a big heater. Any suggestions on what kind of heater to get as a backup I can fit in my sump? Also do I have to buy a second controller as well? My Inkbird has a heater and chiller plug so I assume I cant plug a heater into the chiller part. I was also debating on waiting until I buy an Apex controller and plugging one heater into the apex and one into the inkbird controller. But im not sure if I should wait until I have the money for an Apex to throw in a backup heater. Should i just get a smaller heater with a dial and set it a few degrees under my good titanium heater.. so if my titanium one goes bad then my backup one kicks on even if it keeps it a couple degrees cooler? Not really sure how I should go about doing a second heater for my sump.